Stars Properties and Life Cycle

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Star Properties and Life Cycle WebQuest

In many ways, stars are like humans. Humans have different physical properties and characteristics such as skin or hair color that help us tell each other apart from one another. Just like humans, stars also have unique properties that help us identify them. What properties do stars have? How do you think stars are different form one another?

Throughout our lives, humans undergo many changes; we age, mature and grow old. ASPIRE has a great website which illustrates how stars also experience similar changes. So if stars change, what happens to them at the end of their life? Where are stars born and how long will they shine for? All these questions and more we will investigate and answer as you navigate through this website. All images are courtesy of NASA.

Procedure:

A basic procedure has been outlined below to help you navigate throughout this webiste:

Introduction

Task

Research and Writing

Evaluation

Conclusion

Introduction

Introduction

Stars have both perplexed and intrigued humanity for thousands of years. When we look to the night sky, we can’t help but feel a natural sense of wonder and curiosity. That same inquisitive nature has gripped and engrossed scientists to answer fundamental questions about stars. Luckily, we have a star close by that we can study called the Sun. You know, the star that gives us a nice sun burn when we spend to much time outdoors. The image below is from NASA's SOHO sattelite. Most of the visible universe is comprised of stars. In other words, the universe is made mostly of stars! So by understanding stars, scientists hope to learn more about our universe. In this assignment you investigate how stars differ in their physical properties and lifecycle. You will seek out and answer questions like:

How does star size influence and affect a star’s brightness or luminosity?

What is the relationship between a star’s color and a star’s temperature?

How does the lifecycle of a yellow star like our sun compare to a large massive blue star?

What is the fate of our sun in 5 billion years?

Task

Task

Imagine you have just been given the task of writing an article on stars for your school newspaper. No, not the Hollywood stars that make up our tabloids magazines; but the stars that twinkle in our night sky! Before you write the article, your teacher wants you to conduct some research on star size, brightness, color, and temperature. The teacher also wants you to write about how stars vary in their life cycles. To do this, complete the hand out given to you by the teacher. Once you have completed your research, begin writing your article by summarizing all that you have learned on the back side of the handout. If your Teacher has not already given you a copy of the assignment, you can download it by clicking here. For further assistance, please verify your work by clicking on the various NASA links provided for you on this website. Before we begin this task, a simple procedure is outlined below to help guide you through the assignment:

Begin collecting research by clicking on the “Research Process” page below. Make sure your watch the You tube video, and read as much as you can about stars by visitng all the links provided. Do not move forward until you have answered all the questions on your handout and have visited all the links.

After the research process, begin the writing process by clicking on the “Writing Process” page. Be as descriptive as possible and include factors such as star size, brightness, color, and temperature. The teacher also wants you to write about how stars vary in their life cycles. The article should be well written and consist of at least 8 or more complete sentences. Feel free to use a word processor or computer to type the article.

Finally, evaluate yourself by clicking the “Evaluate” page. Read the rubric and make sure you completed all the necessary requirements. When you feel confident that you have met the rubric rquirements please submit the assignment.

Research Process

Research

We will start the Web Quest by first defining what a star is. NASA defines a star as a sphere of gases held together by it's own gravity. With out going into to much detail, gravity is an important factor in determining the size of a star. Our Sun is your typical average star made mostly of Hydorgen and helium gas. Just like out Sun, stars are made mostly of Hydrogen and Helium are the most abundant elements in our universe. Gravity also play's a major role in the death of a star. To begin your investigation of stars, please watch an amazing Youtube clip on stars. While you watch, please consider factors such as star size and color.

As you saw in the movie, stars vary in their size and color, but stars are also different in their temperature and brightness.

When it comes to star temperature, color determines the relative temperature of a star. I say relative, because all stars are extremely hot. But when we compare star temperatures to each other, some are hotter and some are cooler than others. In general, red or orange stars are cool in temperature and yellowish stars like our sun are average in temperature. Finally, blue or white stars are the hottest stars space.

When you look up to the night sky, you may have noticed that some stars are brighter than other stars. Stars closer to earth obviously appear brighter to us; but what determines the true brightness of a star? Well, a star's brightness is determined by the star’s size. As a star becomes larger, they also become brighter, and as you might have guessed, as stars decrease in size they also become less bright. So, in general, large stars are very bright and smaller stars are dim and less bright. Absolute Magnitude is the term Scientist’s use to describe the true brightness of a star. How bright a star appears from earth is the star’s Apparent Magnitude. Finally, another word scientist’s use to describe star brightness is Luminosity. The diagram below shows the relationship between star color and temperature.

Just like stars have different sizes and temperatures, they also have different life cycles. All stars are born in a nebula, a huge cloud of gas ice and dust. Once a star forms, it will become a main sequence star. A star will spend most of its life in the main sequence phase. Our yellow Sun will spend about 10 billion years of it's life in the main sequence phase. The Sun is about 5 billion years old and will burn brightly for another 5 billion years in the Main Sequence phase. After it runs out of hydrogen fuel, our yellow main sequence Sun will become a Red Giant Star. Our Sun will burn as a Red Giant Star for about a billion years, after which it will shed and discard its outer layers becoming a Planetary Nebula. Inside the Planetary Nebula is the hot glowing core of the Red Giant Star. The outer gases in a Planetary Nebula will slowly escape over a period of a billion years and leave behind a hot White Dwarf star. For more information on the lifecycle of our sun click here.

Blue Stars share a completely different fate than stars like our sun. Just like our Sun, Massive Blue form in nebular clouds of gas ice and dust. However, because of their high temperatures Blue Stars burn through their fuel faster and therefore live much shorter lives—in the millions of years versus billions of years like our Sun. When Massive Blue Stars run out of hydrogen fuel it will become a supergiant star. These stars are absolutely huge in size. Their red color gives away their cool temperatures. Eventually, even a supergiant star runs out of fuel. When this happens, it will create a stellar explosion (exploding star) called a supernova. Depending upon the initial size of the Blue Star, it will become one of two things—a Neutron Star or Black Hole. After it goes supernova, the ultimate fate of a Massive Blue Star will result in the formation of a Black Hole due to the gravitational collapse of its core. For smaller Blue Massive Stars, gravity isn’t quite strong enough to crush the core, and a Neutron Star forms as a result. For more information on the life cycle of stars click here. The diagram below summarizes the information above.

Writing Process

Writing

Now that have conducted your research, you will need to write a formal article on stars for your school newspaper on the backside of the handout. Feel free to type the article if you have access to a word processor or computer; make sure to attach the printed article to the handout.

Remember, to be as descriptive as possible and include factors such as star size, brightness, color, and temperature. The teacher also wants you to write about how stars vary in their life cycles.

The Structure of the Article Should Include:

In the following order:

Heading

Introduction

Body

Conclusion

The article
should be well written and consist of at least ten or more complete sentences. Three of the ten sentences must reference the external links found throughout this website. For more information on writing articles, check out wikiHow or eHow for further assistance. Finally, when you are finished, evaluate yourself by clicking on the "evaluate" page below.

Evaluate

Evaluate Yourself

Use the rubric below to evaluate yourself.

Full Credit

Partial Credit

No Credit

Research Process

Research was thoroughly carried out. Links were visited and carefully read. Questions on the handout were answered in complete sentences.

Research was limited, links were not visited and questions were not answered in complete sentences

Little to no research was carried out. Few to none of the questions were answered.

Writing Process

Article was well written and very descriptive with 8 or more sentences. The article contained a heading, introduction, body and conclusion.

Article was reasonably well written and contained between 4-8 sentences. The article had some structure.

Article was poorly written and contained only a few sentences. Little to no structure was evident

Grammar and Puncuation

Article contained little to no grammar or punctuation errors.

Article contained several grammar or punctuation mistakes.

The article contained numerous grammar and punctuation errors.

Conclusion

Conclusion

In this WebQuest you investigated some of the most amazing objects in our universe—stars!!!! Most of the universe is made up of stars. Stars come in different sizes, colors, and provide the earth with energy. Stars, like humans change through out their lives. for example, in 5 billion years our Sun will swell up into a red giant star. Some stars end their lives in a colossal explosion only to end up as black holes or neutron stars.

If you successfully evaluated yourself and earned full credit; you should be proud. To complete this assignment, you conducted research by visiting numerous websites. You engaged in critical thinking by analyzing various diagrams and pictures. You articulated your thoughts and put them in written format. In the end, you learned a great deal about stars; the most abundant and important objects in the universe!!!!!!

Teacher Page

Teacher Page

Purpose: To investigate how stars differ in their physical properties and lifecycle.

Rationale: Stars are unique in their brightness, temperature, size and lifecycle. It is important that students understand the fundamental elements that make up our universe.
Learner

Learner Description: This web quest was designed for individuals who seek to broaden their scope, knowledge and understanding on the properties and characteristics of stars.

Prerequisites: It is assumed students have learned and mastered elementary and middle school California earth science state standards before embarking upon this assignment.

Objectives:
By the end of this assignment, students will have:

Investigated and discovered the properties and life cycles of stars

Critically analyzed diagrams and pictures

Articulated acquired knowledge into structured coherent sentences

Used an in-depth rubric to self evaluate their own learning

California State Standards Adressed: 2d, Students know that stars differ in their life cycles and that visual, radio, and X-ray telescopes may be used to collect data that reveal those differences.